milestones
A milestone is an important event in the history or development of something or someone.
He said the launch of the party represented a milestone in Zambian history.
他说该党的成立是赞比亚历史上的一个里程碑。
Starting school is a milestone for both children and parents.
开始学校教育既是孩子们也是家长们的一个里程碑。